Apparatus for laying up multiple-ply cross-bonded plywood panels

ABSTRACT

Apparatus for laying up cross-bonded multiple-ply plywood panels comprising a main conveyor line for moving veneer sheets and core sheets, one after the other, through a glue applicator. The applicator applies a glue coating to the upper surfaces of the sheets. The sheets then move to a stacking region where the core and veneer sheets are stacked one on top of the other in the order in which they have been carried on the main conveyor line. Core sheet supply means positioned laterally of the main conveyor line delivers core sheets onto the main conveyor line. Veneer sheet supply means positioned in line with the main conveyor line delivers veneer sheets to the conveyor line. Face veneer sheet supply means superposed over the conveyor line, intermediate the glue applicator and stacking region, delivers uncoated face veneer sheets to be layed on top of a stack of core and veneer sheets in the stacking region.

United States Patent [191 Crawford 51 May 1, 1973 [541 APPARATUS FOR LAYING UP MULTIPLE-FLY CROSS-BONDED [73] Assignee: Leading Plywood Corp., Corvallis,

Oreg.

[22] Filed: Nov. 16, 1970 [21] Appl. No.: 89,746

[56] References Cited UNITED STATES PATENTS 3,616,090 Larson ..156/563 X Primary Examiner-Philip Dier Att0rney-K0lisch & Hartwell 5 7 ABSTRACT Apparatus for laying up cross-bonded multiple-ply plywood panels comprising a main conveyor line for moving veneer sheets and core sheets, one after the other, through a glue applicator. The applicator applies a glue coating to the upper surfaces of the sheets. The sheets then move to a stacking region where the core and veneer sheets are stacked one on top of the other in the order in which they have been carried on the main conveyor line. Core sheet supply means positioned laterally of the main conveyor line delivers core sheets onto the main conveyor line. Veneer sheet supply means positioned in line with the main conveyor line delivers veneer sheets to the conveyor line. Face veneer sheet supply means superposed over the conveyor line, intermediate the glue applicator and stacking region, delivers uncoated face veneer sheets to be layed on top of a stack of core and veneer sheets in the stacking region.

11 Claims, 8 Drawing Figures Patented May 1, 1973 3 Sheets-Sheet 1 John H. Crawford BY JNVENTOR Patented May 1, 1973 John H. Crawford BY INVENTOR 4404 W 3 Sheets-Sheet 2 Patented May 1, 1973 3 Sheets-Sheet 3 JohnHfr'awford I BY INVENTOR PH h rs.

APPARATUS FOR LAYING UP MULTIPLE-PLY CROSS-BONDED PLYWOOD PANELS This invention relates to apparatus for laying up plywood panels.

In the manufacture of plywood panels, a panel generally is laid up having a back veneer sheet forming one outer surface for the panel, a face veneer sheet forming the other outer surface for the panel, and inner plies between the face and back veneer sheets. The inner plies may comprise core sheets or a combination of core and center veneer sheets. In such a panel, the face, back, and center veneer sheets generally are positioned with their grain extending in a common direction and the core sheets are positioned with their grain extending transversely of the grain in the veneer sheets.

A general object of the invention is to provide novel apparatus operable rapidly and efficiently to lay up multiple-ply plywood panels.

Another object is to provide novel apparatus for continuously laying up multiple-ply plywood panels which is compact and requires a minimum amount of floor space.

Yet another object is to provide novel apparatus for laying up multiple-ply plywood panels which includes a main conveyor line for carrying veneer sheets which are to form part of a panel and veneer sheet supply means for delivering such veneer sheets to the main conveyor line with the veneer sheets traveling in the same direction and at substantially the same speed as they are to be moved on the main conveyor line. With such delivery, more accurate alignment and spacing of the veneer sheets on the main conveyor line may be obtained. Also, the main conveyor line may be operated faster to obtain greater production.

More specifically, an object of the invention is to provide apparatus for continuously laying up multiple ply cross-bonded plywood panels which includes a main conveyor line for carrying veneer and core sheets along a path with the grain in the core and veneer sheets extending transversely of each other and with the conveyor line transporting the sheets to a stacking region wherein they are stacked one on top of the other. Also included in the apparatus is veneer sheet supply means for moving veneer sheets onto the conveyor line with the sheets moving at substantially the same speed and in the same direction as the conveyor line, and core sheet supply means disposed laterally of the conveyor line and operable to move core sheets onto the conveyor line with such being interspersed on the conveyor line with veneer sheets from the veneer sheet supply means.

A further object of the present invention is to provide apparatus for supplying to the main conveyor line, presized core sheets made up of multiple edge-connected core pieces, which apparatus stretches. such core sheets, whereby any overlap between adjacent core pieces is removed from the core sheet.

These and other objects and advantages will become more fully apparent as the following description is read in conjunction with the drawings, wherein:

FIG. 1 is a schematic top plan view of plywood lay-up apparatus according to the invention;

FIGS. 2 and 3 are enlarged side elevation views taken generally along lines 2-2 and 3-3, respectively, in FIG. 1;

FIG. 4 is a top plan view of that portion of the apparatus illustrated in FIG. 2;

FIG. 5 is a top plan view of that portion of the apparatus illustrated in FIG. 3;

FIG. 6 is an elevation view of core supply means in the apparatus taken generally along the line 6-6 in FIG. 2;

FIG. 7 is an enlarged view of mechanism in the core supply means taken generally along the line 7-7 in FIG. 6; and

FIG. 8 is a schematic top plan view of another embodiment of plywood lay-up apparatus according to the invention.

Referring now to the drawings, and first specifically to FIG. 1, at 10 is indicated apparatus according to the invention for continuously laying up multiple-ply plywood panels. In general terms, the apparatus includes a main conveyor line 12 which is operable to support veneer and core sheets substantially horizontally and to convey them to the right in FIG. 1. A veneer sheet supply means 14 is disposed adjacent the upstream. end of the main conveyor line and is substantially in line therewith. A core sheet supply means 20 is positioned adjacent the upstream end of main conveyor line 12 and laterally thereof. As will be explained in greater detail below, the core sheet supply means is operable to move a presized core sheet in a direction laterally of the main conveyor line onto the main conveyor line, and the veneer sheet supply means is operable to move veneer sheets in the direction of travel of the 'main conveyor line onto the main conveyor line with veneer sheets and core sheets being interspersed on the main conveyor line.

At 24 is indicated a glue spray-er, or applicator, for applying glue to the upper surfaces of core and veneer sheets carried therethrough on the main conveyor line. Adjacent the downstream end of the main conveyor line, at the far right in FIG. 1, is a stacking support 28 onto which core and veneer sheets may be deposited one after the other from the main conveyor line to form a panel.

Intennediate glue applicator 24 and stacking support 28 is a face veneer supply means 32 superposed over conveyor line 12. The face veneer supply means is operable to feed face veneer sheets toward the stacking support.

Referring now to FIGS. 2 and 4, veneer sheet supply means 14 includes a pair of veneer sheet stack supports 40, 42 for supporting stacks of veneer, such as a stack of center veneer sheets indicated at 44 and a stack of back veneer sheets indicated at 46. The stack supports comprise conventional scissor-lift mechanisms which are operable automatically to maintain the tops of stacks 44, 46 at a substantially constant level.

Center veneer sheet storage is provided by a conveyor 50 at the left of stack support 40 in FIGS. 2 and 4. A reserve stack of center veneer sheets 52 is supported on conveyor 50.

Positioned to one side of stack support 42 and stack 46 in FIG. 4 is a back veneer sheet storage 54 on which is supported a reserve stack of back veneer sheets 56.

Mounted on a frame 60 above stack supports 40, 42, and above the level at which the stack supports maintain the tops of stacks 44, 46, is a vacuum belt conveyor 64. Conveyor 64 includes a pair of endless, elongated,

parallel and laterally spaced porous belts 66 having substantially horizontal lower reaches. The belts are power driven, whereby their lower reaches travel to the right in FIGS. 2 and 4. The belts are trained about a vacuum chamber 68. The vacuum chamber may be evacuated by a vacuum pump (not shown) which is connected to chamber 68 through a conduit 70. Chamber 68 has openings along its lower margin over which the belts pass, whereby air may be drawn through the belts and into the chamber.

Mounting vacuum belt conveyor 64 on frame 60 are a pair of rack and pinion gear assemblies 74, 76 (see FIG. 2) adjacent opposite ends of the belt conveyor. These assemblies provide for vertical movement of conveyor 64 relative to frame 60. Each of assemblies 74, 76, includes a vertical rack gear connected to the vacuum belt conveyor and a pinion gear rotatably mounted on frame 60. The pinion gear is power-driven for rotation about a horizontal axis, with its teeth intermeshing with the teeth on the rack gear. Rotation of the pinion gear in one direction lowers the vacuum belt conveyor, whereby the lower reaches of belts 66 may contact the upper surfaces of the top veneer sheets in stacks 44, 46. With a subatmospheric pressure produced in chamber 68, the veneer sheets contacted will be held against the lower reaches of the belts. Reverse rotation of the pinion gear raises the vacuum belt conveyor, to raise such sheets from the stacks. Driving of the belts moves the veneer sheets held thereagainst to the right in FIGS. 2 and 4.

Also included in the veneer sheet supply means are a series of parallel, laterally spaced, power-driven, endless, inclined belts 80 positioned to the right of and somewhat below vacuum belt conveyor 64 (see FIGS. 2 and 4).- The upper reaches of belts 80 are inclined downwardly, progressing away from vacuum belt conveyor 64 and toward the main conveyor line. Belts 80 are adapted to receive veneer sheets transported thereto by vacuum belts 66. When belts 80 are driven, their upper reaches move to the right in FIGS. 2 and 4 to move veneer sheets supported thereon onto the main conveyor line. The veneer sheets are moved from the inclined belts onto the main conveyor line in the same direction and at substantially the same speed as the main conveyor line is moving. 1

Vacuum belt conveyor 64 is actuated automatically by conventional controls, to supply veneer sheets to inclined belts 80 only at such time as belts 80 are empty. Inclined belts 80, in turn, are controlled automatically for intermittent operation, to supply center and back veneer sheets to main conveyor line 12 in spaced relationship, as will be described in greater detail below.

Referring to FIGS. 4 and 6, core sheet supply means 20 includes a core sheet stack support 86. Stack support 86 is a conventional scissors lift mechanism which is controlled automatically to maintain the top surface ofa stack of presized core sheets 88 supported thereon at a substantially constant level. As is best seen in FIG. 4, each core sheet in stack 88 may be formed of multiple, narrow core pieces 89 joined together in edgeabutting relationship by a pair of strings 90 adjacent opposite side margins of the core sheet. The strings extend across the abutting edges of the core pieces and are glued to the top surfaces thereof to form an integral presized sheet of core material.

Positioned adjacent core sheet stack support 86 is a core sheet stack storage support 91 which is operable to store a reserve stack of core sheets 92.

Supported above stack support 86 is a vacuum belt conveyor 94, which is somewhat similar to that previ ously described at 64 in the veneer sheet supply means. Vacuum belt conveyor 94 includes a single endless, elongated, porous vacuum belt 96 trained over a vacuum chamber 98. The vacuum chamber may be evacuated by a vacuum pump connected thereto by a conduit. Vacuum belt conveyor 94 is mounted for vertical movement on rack and pinion gear assemblies similar to assemblies 74, 76 described above. Such assemblies are operable to lower vacuum belt 96 to place its horizontal lower reach against the upper surface of the top core sheet in stack 88. With a subatmospheric pressure produced in vacuum chamber 98, the core sheet contacted will be held against belt 96, and raising of the vacuum belt conveyor 94 will lift such core sheet from the stack. Belt 96 is power driven whereby its lower reach travels to the right in FIG. 6. A core sheet lifted from stack 88 thus may be moved with the lower reach of belt 96.

Positioned below and to the right of vacuum belt conveyor 94 in FIG. 6, and toward the viewer from conveyor 94 in FIG. 2, are a pair of elongated, endless, power-driven belts 100, which have substantially horizontal upper reaches. These belts are driven, whereby their upper reaches travel to the right in FIG. 6 and toward the viewer in FIG. 2 at a greater speed than belt 96. With belts 100 traveling faster than belt 96, when the leading edge of a core sheet is deposited on belts 100 by belt 96, the more rapid travel of belts 100 tends to stretch the core sheet in the direction of its leading edge to draw out any possible overlap which may have developed between adjacent core pieces within the core sheet. Conventional sensing means connected to drive means for belts 100 is operable to stop these belts when a core sheet is moved into position in line with main conveyor line 12.

Positioned adjacent belts 100 are a series of powerdriven jump rolls 104, as is best seen in FIGS. 2 and 7. The jump rolls are driven rotatably, in a clockwise direction as viewed in FIGS. 2 and 7, about axes which extend parallel to the direction of travel of belts 100. The jump rolls are mounted on a common support 106 for vertical shifting between a normally lowered position, illustrated in solid outline in FIG. 7, where the tops of the rolls are below the level of the top reaches of belts 100, and a raised position, illustrated in dotdashed outline, where the tops of the rolls are above the tops of belts 100.

Support 106 is swingably mounted on a frame 110 through a series of upwardly inclined swing arms 112. The swing arms are journaled at their upper set of ends to support 106 and are joumaled at their lower set of ends on frame 110. An elongated inclined lever arm 114 is journaled at its upper end to support 106, at its center to frame 110, and at its lower end to the rod end of a fluid-operated ram 120. Extension of ram swings lever arm 114 about its central journal connection with frame 110, which raises support 106 and rolls 104 to their raised positions. Contraction of ram 120 lowers the support and rolls. Swing arms 112 are of equal length and serve to maintain the tops of rolls 104 in a common, substantially horizontal plane as they are raised and lowered. With the rolls in their normally lowered position, a core sheet from stack 88 may be moved fully onto belts 100 and into line with main conveyor line 12. Ram 120 then may be extended to raise rolls 104, which rolls engage the undersurface of such core sheet, lift it from belts 100 and move the core sheet onto main .conveyor line 12.

Automatic control and sequencing mechanism interconnects the means for driving veneer sheet supply means 14 and core sheet supply means 20, whereby veneer sheets and core sheets are deposited, one after the other, on main conveyor line 12 with the core sheets and veneer sheets interspersed.

Referring now to FIG. 3 and describing the panel stacking support 28 in greater detail, it comprises a support platform 142 onto which veneer sheets and core sheets may be deposited one after the other from the main conveyor line, with a sheet deposited being superposed over a sheet immediately preceding it on the stacking support. The stacking support further includes a scissor-lift mechanism 144 which lowers the support platform incrementally to maintain the top surface of a stack of veneer and core sheets deposited thereon at a level slightly below the level of the top of main conveyor line 12.

Disposed intermediate stacking support 28 and glue applicator 24 is the face veneer supply means 32. Referring to FIGS. 3 and 5, face veneer supply means 32 includes a face veneer stack support 152, which may be a scissors-lift mechanism. Such mechanism is operable to maintain the top of a stack of face veneers, indicated generally at 154, with its top surface at a substantially constant elevation. Supported above stack support 152 and above stack 154 is a vertically shiftable, power-driven vacuum belt conveyor 158 which is substantially similar to that previously described at 64. Belt conveyor 158 is operable to engage the upper surface of a face veneer sheet on the top of stack 154 and to convey such to the right in FIGS. 3 and 5, onto a series of parallel, laterally spaced, inclined, power-driven endless belts 164. Belts 164 are positioned below belt conveyor 158 and incline downwardly on progressing from belt conveyor 158 toward stacking support 28. The face veneer supply means is operable to move a presized sheet of face veneer from stack 154 onto a stack of core and veneer sheets on support platform 142. Automatic control means are connected to the face veneer supply means, whereby a face veneer sheet with no glue coating is transported to the support platform after a predetermined number of core and veneer sheets have been stacked thereon.

Describing now the operation of the apparatus, to produce five-ply plywood panels, presized center and back veneer sheets are disposed in stacks 44, 46, respectively, with the grain in the sheets extending transversely of conveyor belts 66, and transversely of main conveyor line 12. The presized core sheets are disposed in stack 88 with the grain in the individual core pieces within the core sheets substantially paralleling the direction of travel of main conveyor line 12. Face veneer sheets in stack 154 are positioned with their grain extending transversely of the main conveyor line.

Vacuum belt conveyor 64 is lowered to engage the and then is raised to lift such sheets from their respective stacks. The belts in this belt conveyor then are driven to place a back and a center sheet on belts 80. Vacuum belt conveyor 94 above the stack of core sheets is actuated also to pick up the top presized core sheet from stack 88 and to convey it onto belts 100. Belts 100 move such core sheet into a position in line with the upstream end of main conveyor line 12 and also stretch the core sheet to remove any overlap between adjacent core pieces within the core sheet.

Operation of belts 80 moves a back veneer sheet onto conveyor line 12 and belts 80 then are stopped. Jump rolls 104 then are raised to move the core sheet from belts 100 onto the main conveyor in a position directly behind the back veneer sheet. As the core sheet is carried on the main conveyor line and clears the downstream ends of belts 80, these belts are operated once again to move the center veneer sheet supported thereon onto the main conveyor line. Operation of vacuum belt conveyor 94, belts 100, and jump rolls 104 then place another core sheet on main conveyor line 12 directly behind the center veneer sheet.

,As this other core sheet is being moved onto the main conveyor line, vacuum belt conveyor 64 places another back and center veneer sheet on inclined belts 80 for another cycle.

As the back and center veneer sheets and core sheets are conveyed one after the other along the main conveyor line, through glue applicator 24, a glue coating is applied to their upper surfaces. The veneer and core sheets then are placed one after another on stacking support 28. After a back veneer sheet, core sheet,

upper surfaces of the top sheets in each of stacks 44, 46 7 center veneer sheet, and another core sheet have been deposited one on top of the other, in that order, on the stacking support with glue therebetween, a face veneer sheet is deposited thereon from face veneer supply means 32. In this manner a five-ply plywood panel is formed having alternating layers of veneer and core sheets with the grain in the core sheets extending transversely of the grain in the veneer sheets.

The above-described operation may be varied to produce plywood panels having any number of alternating core and veneer sheet layers.

Referring now to FIG. 8, another embodiment of the invention is illustrated at which includes a second core sheet supply means 170. Core sheet supply means is similar to that described at 20 and is positioned laterally to the opposite side of main conveyor line 12 from core sheet supply means 20, All of the other component parts of apparatus 160 are similar to that previously-described for apparatus 10 of the first embodiment of the invention.

This modified plywood panel lay-up apparatus is operable to lay up plywood panels when it is desired to place a pair of core sheets in face-to-face contact with each other between a pair of veneer sheets. Explaining further, and describing the operation of this modified apparatus, a back veneer sheet is placed on conveyor line 12, followed by a core sheet from core sheet supply means 170. This core sheet is followed directly by a core sheet supplied from core sheet supply means 20. Once the core sheet from supply means 20 has cleared the downstream ends of belts 80, another veneer sheet may be placed directly behind it on conveyor line 12. The veneer and core sheets thus follow one another along the line with the pattern being veneer sheet, core sheet, core sheet. After this combination of veneer sheet, core sheet, core sheet has been conveyed through the glue applicator and onto the stacking support 28, a face veneer sheet is placed thereover from face veneer supply means 32 to form a four-ply panel having exterior veneer sheets with their grain extending lengthwise of the panel and a pair of core sheets between the outer veneer sheets with their grain extending transversely of the panel.

Such apparatus is compact, since the core sheet supply means is disposed laterally of the main conveyor line and the veneer sheet supply conveyors extend over the region onto which the core sheets are supplied to the conveyor line. Further, the face veneer sheet supply is superposed over the conveyor line to conserve space. The apparatus is rapid and efficient in its operation since the back and veneer sheets may be supplied to the coneyor line traveling in the same direction and at the same speed as the conveyor line. This permits more accurate and closer spacing between the veneer sheets and core sheets as they are placed on the conveyor line.

While preferred embodiments of the invention have been described, it should be apparent to those skilled in the art that further variations and modifications are possible without departing from the spirit of the invention.

It is claimed and desired to secure by Letters Patent:

1. Apparatus for laying up multiple-ply cross-bonded plywood panels comprising an elongated main conveyor line for carrying interspersed veneer sheets one after another horizontally and in one direction therealong with the sheets oriented on the conveyor line as they are to be layed up in the panel,

first veneer sheet supply means adjacent the upstream end of the main conveyor line and disposed substantially in line therewith including a veneer sheet stack support for supporting a stack of veneer sheets with the veneer sheets oriented as they are to be carried on the main conveyor line, and veneer sheet conveyor means operable to remove a veneer sheet from the top of the stack and move thesame in said one direction onto said main conveyor line,

second veneer sheet supply means positioned adjacent the upstream end of the main conveyor line and laterally thereof, including a veneer sheet stack support for supporting a stack of veneer sheets in a position spaced laterally of the main conveyor line with the veneer sheets oriented as they are to be carried on the main conveyor line, and veneer sheet conveyor means operable to remove a veneer sheet from the stack and move the same laterally of the main conveyor line 'onto said main conveyor line, including means for initiating movement of a veneer sheet in the direction of the main conveyor line,

a glue applicator disposed downstream in said main conveyor line from said first and second veneer sheet supply means for applying glue to the upper surfaces of veneer sheets carried on said main conveyor line, and

a stacking support onto which veneer sheets may be deposited, one after another, from the main conveyor line with a sheet deposited being superposed over a sheet immediately preceding it on the stacking support.

2. Apparatus for laying up multiple-ply cross-bonded plywood panels comprising an elongated main conveyor line for carrying interspersed veneer and core sheets one after another horizontally and in one direction therealong with the sheets oriented on the conveyor line as they are to be layed up in the panel,

veneer sheet supply means adjacent the upstream end of the main conveyor line and disposed substantially in line therewith including a veneer sheet stack support for supporting a stack of veneer sheets with the veneer sheets oriented as they are to be carried on the main conveyor line, and veneer sheet conveyor means operable to lift a veneer sheet from the top of the stack and move the same in said one direction onto said main conveyor line,

core sheet supply means positioned adjacent the upstream end of the main conveyor line and laterally thereof, including a core sheet stack support for supporting a stack of core sheets in a position spaced laterally of the main conveyor line with the core sheets oriented as they are to be carried on the main conveyor line, and core sheet conveyor means operable to remove a core sheet from the stackand move the same laterally of the main conveyor line onto said main conveyor line and ineluding means for initiating movement of a core sheet in the direction of movement of the main conveyor line,

a glue applicator disposed downstream in said main conveyor line from said core and veneer sheet supply means for applying glue to the upper surfaces of core and veneer sheets carried one after the other on said main conveyor line, and

a stacking support onto which core and veneer sheets may be deposited, one after another from the main conveyor line with a sheet deposited being superposed over a sheet immediately preceding it on the stacking support.

3. The apparatus of claim 2, wherein said core sheet conveyor means comprises a first power-driven conveyor section operable to initiate movement of a core sheet from the core sheet stack toward said main conveyor line and a second power-driven conveyor section operable to receive a core sheet from said first conveyor section and to move the core sheet onto the main conveyor line, said second conveyor section being driven at a speed greater than said first conveyor section.

4. The apparatus of claim 2, wherein said veneer sheet conveyor means comprises a vacuum belt conveyor including an elongated, endless, power-driven vacuum belt having a substantially horizontal lower reach which substantially parallels the main conveyor line, overlies the veneer sheet stack support, and is movable under power in the direction of said main conveyor line, and means mounting said veneer sheet stack support and vacuum belt for shifting vertically toward and away from each other.

5. The apparatus of claim 4, wherein said veneer sheet conveyor means is spaced above said main conveyor line and further comprises an elongated conveyor element having an upstream end disposed adjacent said vacuum conveyor belt and extending at an incline downwardly from the vacuum conveyor belt in the direction of the main conveyor line and over the region of the main conveyor line onto which the core sheet conveyor means deposits core sheets, said element being operable to receive a veneer sheet from the vacuum conveyor belt and transport the same onto said main conveyor line in a region downstream from the region in which the core sheet conveyor deposits core sheets.

6. The apparatus of claim 5, wherein said conveyor element comprises an endless, elongated belt having an upper reach adapted to support a veneer sheet, and which further comprises power-drive means operatively connected thereto actuatable intermittently for driving said upper reach in the direction of said main conveyor line in timed relation with the operation of the core supply means to deposit core sheets and veneer sheets in following relation on the main conveyor line.

7. The apparatus of claim 3, wherein said first conveyor section comprises a vacuum chamber in which a lower-than-atmospheric pressure may be produced disposed over said core sheet stack support, and an endless, elongated, power-driven, porous vacuum belt trained over said vacuum chamber and positioned above the core sheet stack support with a lower reach of the belt extending laterally of the main conveyor line and positioned to engage the upper surface of a top core sheet on said core sheet stack support, with openings in the belt communicating with the interior of said chamber, said belt on being driven and with a lower-than-atmospheric pressure in the vacuum chamber being operable to hold a core sheet against its lower reach and move the same toward the main conveyor line.

8. The apparatus of claim 7, wherein said second conveyor section comprises a power-driven conveyor belt having a substantially horizontal upper reach positioned below the level of said vacuum belt and extending transversely of the main conveyor line, said second conveyor belt being adapted to receive a core sheet from said first conveyor section and operable to move said core sheet transversely of said main conveyor line into a position in line with said main conveyor line, and said means for initiating movement of a core sheet in the direction of movement of the main conveyor line comprises a plurality of power-driven rollers adjacent said second conveyor belt rotatable under power about axes extending transversely of the main conveyor line, said rollers being mounted for shifting between a first position in which they are positioned for engaging a core sheet on the second conveyor belt and a second position out of engagement with a core sheet on the second conveyor belt.

9. The apparatus of claim 2, which further comprises face veneer sheet supply means intermediate the glue applicator and stacking support including a face veneer stack support for supporting a stack of face veneer sheets with said veneer sheets oriented as they are to be layed up in a panel, and a face veneer conveyor for moving a face veneer sheet from said stack toward said stackin ghsupport.

10. e apparatus of claim 7, which further comprises means for producing relative vertical shifting of said first conveyor section and said core sheet stack support toward and away from each other.

11. The apparatus of claim 9, wherein said face veneer stack support and face veneer conveyor are superposed over said main conveyor line. 

2. Apparatus for laying up multiple-ply cross-bonded plywood panels comprising an elongated main conveyor line for carrying interspersed veneer and core sheets one after another horizontally and in one direction therealong with the sheets oriented on the conveyor line as they are to be layed up in the panel, veneer sheet supply means adjacent the upstream end of the main conveyor line and disposed substantially in line therewith including a veneer sheet stack support for supporting a stack of veneer sheets with the veneer sheets oriented as they are to be carried on the main conveyor line, and veneer sheet conveyor means operable to lift a veneer sheet from the top of the stack and move the same in said one direction onto said main conveyor line, core sheet supply means positioned adjacent the upstream end of the main conveyor line and laterally thereof, including a core sheet stack support for supporting a stack of core sheets in a position spaced laterally of the main conveyor line with the core sheets oriented as they are to be carried on the main conveyor line, and core sheet conveyor means operable to remove a core sheet from the stack and move the same laterally of the main conveyor line onto said main conveyor line and including means for initiating movement of a core sheet in the direction of movement of the main conveyor line, a glue applicator disposed downstream in said main conveyor line from said core and veneer sheet supply means for applying glue to the upper surfaces of core and veneer sheets carried one after the other on said main conveyor line, and a stacking support onto which core and veneer sheets may be deposited, one after another from the main conveyor line with a sheet deposited being superposed over a sheet immediately preceding it on the stacking support.
 3. The apparatus of claim 2, wherein said core sheet conveyor means comprises a first power-driven conveyor section operable to initiate movement of a core sheet from the core sheet stack toward said main conveyor line and a second power-driven conveyor section operable to receive a core sheet from said first conveyor section and to move the core sheet onto the main conveyor line, said second conveyor section being driven at a speed greater than said first conveyor section.
 4. The apparatus of claim 2, wherein said veneer sheet conveyor means comprises a vacuum belt conveyor including an elongated, endless, power-driven vacuum belt having a substantially horizontal lower reach which substantially parallels the main conveyor line, overlies the veneer sheet stack support, and is movable under power in the direction of said main conveyor line, and means mounting said veneer sheet stack support and vacuum belt for shifting vertically toward and away from each other.
 5. The apparatus of claim 4, wherein said veneer sheet conveyor means is spaced above said main conveyor line and further comprises an elongated conveyor element having an upstream end disposed adjacent said vacuum conveyor belt and extending at an incline downwardly from the vacuum conveyor belt in the direction of the main conveyor line and over the region of the main conveyor line onto which the core sheet conveyor means deposits core sheets, said element being operable to receive a veneer sheet from the vacuum conveyor belt and transport the same onto said main conveyor line in a region downstream from the region in which the core Sheet conveyor deposits core sheets.
 6. The apparatus of claim 5, wherein said conveyor element comprises an endless, elongated belt having an upper reach adapted to support a veneer sheet, and which further comprises power-drive means operatively connected thereto actuatable intermittently for driving said upper reach in the direction of said main conveyor line in timed relation with the operation of the core supply means to deposit core sheets and veneer sheets in following relation on the main conveyor line.
 7. The apparatus of claim 3, wherein said first conveyor section comprises a vacuum chamber in which a lower-than-atmospheric pressure may be produced disposed over said core sheet stack support, and an endless, elongated, power-driven, porous vacuum belt trained over said vacuum chamber and positioned above the core sheet stack support with a lower reach of the belt extending laterally of the main conveyor line and positioned to engage the upper surface of a top core sheet on said core sheet stack support, with openings in the belt communicating with the interior of said chamber, said belt on being driven and with a lower-than-atmospheric pressure in the vacuum chamber being operable to hold a core sheet against its lower reach and move the same toward the main conveyor line.
 8. The apparatus of claim 7, wherein said second conveyor section comprises a power-driven conveyor belt having a substantially horizontal upper reach positioned below the level of said vacuum belt and extending transversely of the main conveyor line, said second conveyor belt being adapted to receive a core sheet from said first conveyor section and operable to move said core sheet transversely of said main conveyor line into a position in line with said main conveyor line, and said means for initiating movement of a core sheet in the direction of movement of the main conveyor line comprises a plurality of power-driven rollers adjacent said second conveyor belt rotatable under power about axes extending transversely of the main conveyor line, said rollers being mounted for shifting between a first position in which they are positioned for engaging a core sheet on the second conveyor belt and a second position out of engagement with a core sheet on the second conveyor belt.
 9. The apparatus of claim 2, which further comprises face veneer sheet supply means intermediate the glue applicator and stacking support including a face veneer stack support for supporting a stack of face veneer sheets with said veneer sheets oriented as they are to be layed up in a panel, and a face veneer conveyor for moving a face veneer sheet from said stack toward said stacking support.
 10. The apparatus of claim 7, which further comprises means for producing relative vertical shifting of said first conveyor section and said core sheet stack support toward and away from each other.
 11. The apparatus of claim 9, wherein said face veneer stack support and face veneer conveyor are superposed over said main conveyor line. 